1. See,e.g.,H. Harari: inPhenomenology of Particles at High Energies, Proceedings of the Fourteenth Scottish Universities Summer School in Physics, 1973, edited byR. L. Crawford andR. Jennings (London, 1974).
2. For a recent review and a complete list to the original references, seeM. Moshe:Phys. Rep. C,37, 255 (1978).
3. D. J. Scalapino andR. L. Sugar:Phys. Rev. D,8, 2284 (1973);R. C. Arnold:Phys. Lett. B,67, 91 (1977);Phys. Rev. D,16, 1545 (1977), and references therein;R. C. Arnold andG. H. Thomas:Phys. Rev. D,13, 2013 (1976).
4. V. Yakovlev, S. Nikolsky andV. Pavljuchenko:Proceedings of the XV International Cosmic Ray Conference, Vol.7 (Plovdiv, 1977), p. 115;Brazil-Japan Emulsion Collaboration:Proceedings of the XV International Cosmic Ray Conference, Vol.7 (Plovdiv, 1977), p. 208; see alsoG. Yodh:Proceedings of the XIV International Cosmic Ray Conference (Munich, 1975);C. B. A. McCusker:Phys. Rep. C,20, 229 (1975).
5. J. D. Bjorken:International Symposium on Lepton and Photon Interactions at High Energies, Hamburg, 1977 (unpublished).